Battery cells, battery devices and power-consuming devices

Abstract

The present application relates to the field of battery technology, and specifically discloses a battery cell, a battery device, and an electrical device, including a shell and an electrode assembly, wherein the electrode assembly includes a main body and a plurality of pole ears extending from the main body, the main body includes a plurality of pole pieces and a plurality of diaphragm layers stacked, and along the height direction of the main body, a receiving space located on one side of the main body or two receiving spaces located on different sides of the main body is formed in the shell; the main body has pole ears extending from the end face toward the receiving space, and each diaphragm layer has a lug extending toward the end of the receiving space, and the lugs and pole ears on the same side of the main body are accommodated in the same receiving space, and the lugs are fixedly connected to the shell. When the internal part of the battery cell of the present invention reaches the shrinkage temperature, the end of each diaphragm layer with the lug protruding therefrom is limited in shrinkage by virtue of the connection between the lug and the shell, thereby reducing the possibility of the pole piece edge being exposed, thereby reducing the risk of the edge of the pole pieces of opposite polarity contacting and short-circuiting.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery device and an electrical device. Background Art

[0002] Energy conservation and emission reduction are the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages in energy conservation and environmental protection. For electric vehicles, battery technology is an important factor in their development.

[0003] In actual use, the battery has a short circuit problem caused by thermal runaway, which will further cause the temperature inside the battery to rise sharply, posing a hidden danger to the safety of the battery. Specifically, the reason why thermal runaway causes short circuit is that the thermal runaway phenomenon is accompanied by the release of high-temperature and high-pressure gas, and the adjacent battery cells heat up accordingly, which in turn causes the internal diaphragm to shrink and deform due to heat, resulting in the isolation failure of the diaphragm and the direct contact of the pole pieces with opposite polarities, causing a short circuit. Summary of the invention

[0004] In view of the above problems, the present application provides a battery cell, a battery device and an electrical device, which can reduce the possibility of diaphragm isolation failure and reduce the risk of short circuit caused by exposing the edge of the electrode.

[0005] The first aspect of the present application provides a battery cell, comprising: a shell and an electrode assembly contained in the shell, the electrode assembly comprising a main body and a plurality of pole ears extending from the main body, the main body comprising a plurality of pole sheet layers and a plurality of diaphragm layers stacked in layers, the pole sheet layers and the diaphragm layers being alternately stacked, any two adjacent pole sheet layers in the plurality of pole sheet layers having opposite polarities, and each diaphragm layer extending beyond an edge of the pole sheet layer in a height direction of the main body;

[0006] Among them, along the height direction of the main body, a receiving space located on one side of the main body or two receiving spaces located on different sides of the main body are formed in the shell; a pole ear extends from the end face of the main body toward the receiving space, and a lug extends from each diaphragm layer toward the end of the receiving space, the lug is integrally connected to the corresponding diaphragm layer, and the lug and the pole ear arranged on the same side of the main body are accommodated in the same receiving space; and the lug is fixedly connected to the shell.

[0007] The battery cell of this embodiment is designed to have a receiving space located on one side of the main body or two receiving spaces located on different sides of the main body in the shell, and each diaphragm layer extends a lug toward the end of the receiving space, and the lug is fixedly connected to the shell. During the operation of the battery cell, when the internal temperature reaches the shrinkage temperature due to thermal runaway, overcharging, etc., the end of each diaphragm layer protruding with the lug is limited in shrinkage by virtue of the connection between the lug and the shell, which can effectively reduce the probability of each diaphragm layer being isolated and failing due to heat shrinkage, thereby reducing the possibility of short-circuiting and generating heat due to the edge contact of any two adjacent electrode layers, thereby improving the thermal stability of the battery cell, thereby reducing the safety hazards of the battery cell.

[0008] In some embodiments of the present application, all lugs accommodated in the same receiving space are arranged as one lug portion or a plurality of lug portions spaced apart from each other; each lug portion is formed by a plurality of lugs stacked and connected, and the lug portion is fixedly connected to the housing.

[0009] By arranging all the lugs accommodated in the same receiving space into one lug portion or multiple lug portions, on the one hand, the multiple lugs constituting the lug portion are stacked and arranged, which can reduce the space occupied by the lugs in their own width direction; on the other hand, compared with each lug being individually connected to the outer shell, this can reduce the assembly and connection steps, which is beneficial to improving the preparation efficiency of the battery cell.

[0010] In some embodiments of the present application, the plurality of lugs constituting the lug portion are connected by bonding or heat-fusion treatment.

[0011] This embodiment makes the structure of the lug portion composed of a plurality of lugs reliable, so that the possibility of the plurality of lugs constituting the lug portion becoming loose during the transportation of the battery cell or the like is low.

[0012] In some embodiments of the present application, a receiving space is formed in the shell, and the plurality of pole ears include a positive pole ear and a negative pole ear. The positive pole ear and the negative pole ear are protruded on the same side of the main body, and the positive pole ear and the negative pole ear are spaced apart along a preset direction, and the preset direction is perpendicular to the height direction of the main body and the thickness direction of the main body; at least part of the protruding ear is arranged between the positive pole ear and the negative pole ear.

[0013] In this embodiment, the protruding ear portion between the positive electrode tab and the negative electrode tab can play an isolating role, so that the positive electrode tab and the negative electrode tab are isolated and do not contact each other to avoid short circuit.

[0014] In some embodiments of the present application, the lug portions are symmetrically arranged with respect to a longitudinal center line of the main body portion.

[0015] This embodiment can make the diaphragm layer bear the force evenly, and can reduce the possibility of the diaphragm layer breaking due to uneven force.

[0016] In some embodiments of the present application, the lug portion includes a connected straight portion and a connecting portion, the straight portion is in contact with the end surface of the main body, the connecting portion is folded relative to the straight portion in a direction away from the main body, and one end of the connecting portion away from the straight portion is fixedly connected to the outer shell; the tab is folded into a plurality of overlapping segments spaced apart along the height direction of the main body, and any two adjacent overlapping segments are opposite and connected.

[0017] In this embodiment, the lugs and the tabs are bent and folded to be accommodated in a receiving space, so that the space occupied by the lugs and the tabs in the height direction of the battery cell can be reduced, thereby effectively improving the overall energy density of the battery cell.

[0018] In some embodiments of the present application, the height of the accommodating space is h, and the sum of the height of the lug in a flattened state and the height of the portion of the diaphragm layer extending beyond the pole piece layer is greater than h.

[0019] In some embodiments of the present application, the difference between the sum of the height of the lug in a flattened state and the height of the portion of the diaphragm layer extending beyond the pole piece layer and h is greater than or equal to 2 mm and less than or equal to 15 mm.

[0020] In some embodiments of the present application, along the height direction of the main body, the pole ear exceeds each lug located in the same receiving space as the pole ear.

[0021] In some embodiments of the present application, along the height direction of the main body, the distance that the pole ear exceeds each lug satisfies that it is greater than or equal to 2 mm and less than or equal to 20 mm.

[0022] In some embodiments of the present application, the lug portion has a first surface and a second surface, the first surface is connected to the housing, and the second surface is away from the first surface; the height of each lug constituting the lug portion gradually increases from the first surface to the second surface in a flattened state.

[0023] In this embodiment, the height of the lugs in the lug portion that are away from the first surface is greater, thereby reducing the possibility of the lugs that are away from the first surface and the isolation layer integrally connected thereto being broken due to tension.

[0024] In some embodiments of the present application, the shell includes a shell and an end cover assembly, the shell has an opening, the end cover assembly includes an end cover and a lower plastic part, the end cover covers the opening, and the lower plastic part is arranged on the side of the end cover facing the electrode assembly; a receiving space is formed in the shell, the receiving space is located between the main body and the end cover assembly, and the lug is fixedly connected to the lower plastic part.

[0025] Since the materials of the diaphragm and the lower plastic part are both polymers with similar material properties, the restrictions on the connection method between the two due to the large difference in material properties can be reduced, making installation easier.

[0026] In some embodiments of the present application, the lower plastic part includes a plastic body and a protrusion, the protrusion is arranged on the side of the plastic body facing away from the end cover, and the lug is connected to the protrusion, which is conducive to improving the structural strength of the lower plastic part.

[0027] In some embodiments of the present application, the protrusion is assembled and connected to the plastic body, the protrusion and the plastic body together define a groove, and the lug and the part are arranged in the groove.

[0028] In some embodiments of the present application, the lug is connected to the lower plastic part by bonding, or the lug is connected to the lower plastic part by hot melting.

[0029] The lug and the lower plastic are connected by an adhesive connection method or a hot-melt connection method, and the connection method is simple and reliable.

[0030] In some embodiments of the present application, the main body is a winding structure formed by stacking two diaphragms and two pole pieces with opposite polarities and winding them along a winding direction, each diaphragm has a plurality of diaphragm layers arranged in sequence along the winding direction, and each pole piece has a plurality of pole piece layers arranged in sequence along the winding direction; or, the main body is a laminated structure formed by stacking a plurality of pole piece layers and a plurality of diaphragm layers.

[0031] The second aspect of the present application provides a battery device, comprising: any one of the battery cells provided in the first aspect of the present application.

[0032] The third aspect of the present application proposes an electrical device, comprising: any one of the battery devices proposed in the second aspect of the present application, the battery device being used to provide electrical energy.

[0033] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the structure of a vehicle according to an embodiment of the present application is schematically shown;

[0035] Figure 2 The structure diagram of a battery device according to an embodiment of the present application is schematically shown;

[0036] Figure 3 The structure diagram of a battery cell according to an embodiment of the present application is schematically shown;

[0037] Figure 4 for Figure 3 An exploded schematic diagram of a battery cell shown in FIG.

[0038] Figure 5 Schematically shows an exploded schematic diagram of a battery cell according to another embodiment of the present application;

[0039] Figure 6 for Figure 3 An exploded schematic diagram of an electrode assembly of a battery cell shown in ;

[0040] Figure 7 A schematic diagram of the matching of the diaphragm and the pole piece of the main body of a battery cell according to an embodiment of the present application;

[0041] Figure 8 A schematic diagram of the coordination of the diaphragm and the pole piece of the main body of a battery cell according to another embodiment of the present application;

[0042] Fig. 9 It is a schematic diagram of the structure of multiple diaphragm layers of the main body in different embodiments of the present application;

[0043] Fig.10 for Figure 3 A top view of a battery cell shown in ;

[0044] Fig.11 for Fig.10 The cross-sectional schematic diagram of the AA direction shown in FIG.

[0045] Fig.12 for Fig.11 A local enlarged view of point B shown in FIG.

[0046] Fig.13 The figure schematically shows a partially enlarged cross-section of a battery cell according to another embodiment of the present application.

[0047] Description of reference numerals:

[0048] 1000. Vehicles;

[0049] 100. Battery device;

[0050] 10. Battery cell assembly; 11. Battery cell; 110. Electrode assembly; 111. Pole ear; 111A. Positive pole ear; 111B. Negative pole ear; 113. Main body; 1131. Pole sheet layer; 1132. Diaphragm layer; 1133. Lug; 1134. Lug portion; 1134a. Straight portion; 1134b. Connecting portion; 1135. Pole sheet; 1136. Straight section; 1137. Curved section; 1138. Diaphragm; 120. Shell; 121. Shell; 122. End cap assembly; 1221. End cap; 1222. Lower plastic part; 1223. Plastic body; 1224. Protrusion; 123. Accommodating space; 130. Positive terminal; 140. Negative terminal;

[0051] 20. Box; 21. First box; 22. Second box;

[0052] 200, controller;

[0053] 300. Motor. DETAILED DESCRIPTION

[0054] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0056] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0057] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0058] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0059] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0060] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0061] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0062] Most of the safety issues of batteries in actual applications are caused by thermal runaway. One of the safety issues is that thermal runaway batteries will produce high-temperature gas, and the heat will be transferred to adjacent battery cells, causing the adjacent battery cells to heat up rapidly. When the temperature inside the battery cells reaches the shrinkage temperature, the diaphragm shrinks, and the size of the diaphragm is reduced, causing the pole pieces with opposite polarities to contact and short-circuit.

[0063] When the electrode assembly of the battery cell is a winding structure, the negative electrode sheet, the separator, and the positive electrode sheet are wound along the length direction, and the winding start end of the separator usually exceeds the winding end of the electrode sheet, and the winding end usually exceeds the terminal end of the electrode sheet. In addition, since the negative electrode sheet, the separator, and the positive electrode sheet are all wound to form multiple layers, and each layer of the separator is sandwiched between two adjacent layers of electrode sheets with opposite polarities, the shrinkage creep of each layer of the separator along the winding direction is limited, so the shrinkage rate of the separator length is small.

[0064] When the electrode assembly of the battery cell is a laminated structure, the diaphragm is usually a continuous strip structure, and the diaphragm is folded back and forth in a Z-shape, so that the Z-shaped diaphragm separates two adjacent pole pieces. For similar reasons, each layer of the continuous strip diaphragm is sandwiched between two adjacent pole pieces, and the shrinkage creep of the diaphragm along the length direction is limited, so the shrinkage rate of the diaphragm length is small.

[0065] In general, when the temperature inside the battery cell reaches the shrinkage temperature, the diaphragm shrinks severely along the height direction of the electrode assembly, so that the diaphragm's isolation effect on the edge of the electrode piece along the height direction of the electrode assembly fails, resulting in the edges of two adjacent electrode pieces with opposite polarities contacting and short-circuiting.

[0066] In the present application, the main body is designed so that each diaphragm layer extends with a lug, and the lug and the pole lug arranged on the same side of the main body are accommodated in the same receiving space, and the receiving space for accommodating the pole lug is used to accommodate the lug part at the same time. The lug is designed to be fixedly connected to the outer shell, and the diaphragm layer extending from the lug is pulled by means of the fixed connection between the lug and the outer shell, so that the shrinkage of the two ends of each diaphragm layer is restricted, so as to reduce the possibility of failure of the isolation effect of the diaphragm layer.

[0067] The battery involved in the embodiment of the present application can be used in, but not limited to, electrical devices such as vehicles, ships or aircraft. A power supply system comprising the battery cells, batteries, etc. involved in the present application can be used to form the electrical device.

[0068] In the embodiments of the present application, the electric device using the battery as the power source may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0069] It should be understood that the technical solutions described in the embodiments of the present application are not limited to the batteries and electrical devices described above, but can also be applied to all batteries including a box and electrical devices using batteries. However, for the sake of simplicity, the following embodiments are explained using electric vehicles as examples.

[0070] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 is provided inside the vehicle 1000, and the battery device 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery device 100 may be used to power the vehicle 1000, for example, the battery device 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery device 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0071] In some embodiments of the present application, the battery device 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0072] Figure 2 FIG. 1 is a schematic diagram showing the structure of a battery device 100 according to an embodiment of the present application. Figure 2 As shown, the battery apparatus 100 (Battery Apparatus) mentioned in the embodiment of the present application may include one or more battery cell assemblies 10 for providing voltage and capacity. The battery cell assembly 10 (Battery Cell Assembly) may include a plurality of battery cells 11, and the plurality of battery cells 11 are connected in series, in parallel or in mixed connection through a busbar component.

[0073] In some embodiments, a battery cell assembly 10 (Battery Cell Assembly) is generally formed by arranging a plurality of battery cells 11 .

[0074] As an example, the battery cell assembly 10 may be a battery module (Battery Module), and the battery module is formed by arranging and fixing a plurality of battery cells 11 to form an independent module. As an example, the battery module may be formed by bundling a plurality of battery cells 11 by a cable tie.

[0075] In some embodiments, Figure 2 As shown, the battery device 100 may be a battery pack, which includes a box 20 and one or more battery cell assemblies 10, and the battery cell assemblies 10 are contained in the box 20. The box 20 may be a simple three-dimensional structure such as a single cuboid, cylinder, or sphere, or a complex three-dimensional structure composed of simple three-dimensional structures such as cuboids, cylinders, or spheres. The material of the box 20 may be an alloy material such as aluminum alloy, iron alloy, or a polymer material such as polycarbonate, polyisocyanurate foam plastic, or a composite material such as glass fiber and epoxy resin.

[0076] As an example, the battery cell assembly 10 may be a battery module, and the battery cell assembly 10 may be accommodated in the box body 20 by fixing the battery module in the box body 20 .

[0077] As an example, the battery cell assembly 10 may also be accommodated in the case 20 by directly fixing the plurality of battery cells 11 to the case 20 .

[0078] As an example, the box 20 may include a first box 21 and a second box 22. The first box 21 and the second box 22 are buckled together to form a closed space inside the box 20 to accommodate the battery cell assembly 10. The closed space here means covering or closing, which may be unsealed or sealed to prevent liquid or other foreign matter from affecting the charging or discharging of the battery cell 11. The first box 21 may be a top cover or a bottom plate.

[0079] As an example, the box body 20 may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that a closed space is formed inside the box body 20 to accommodate the battery cell assembly 10.

[0080] In some embodiments, the box 20 can be used as a part of the chassis structure of the vehicle. For example, part of the box 20 can become at least a part of the floor of the vehicle, or part of the box 20 can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0081] The battery cell 11 provided in the embodiment of the present application may be a secondary battery. A secondary battery refers to a battery cell 11 that can be continuously used by activating active materials by charging after the battery cell 11 is discharged.

[0082] The battery cell 11 may be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel metal hydride battery, a nickel cadmium battery, a lead storage battery, etc., and the embodiments of the present application do not limit this. As an example, the battery cell 11 may be a cylindrical battery cell, a prismatic battery cell, or a battery cell 11 of other shapes, and the prismatic battery cell includes a square shell battery cell, a blade-shaped battery cell, and a multi-prismatic battery cell, and the multi-prismatic battery cell is, for example, a hexagonal battery cell, etc., and the present application has no special restrictions.

[0083] like Figures 3 to 5 As shown, the battery cell 11 provided in the embodiment of the present application includes a housing 120, an electrode assembly 110 and an electrolyte. The electrode assembly 110 is a component where an electrochemical reaction occurs in the battery cell 11. The electrode assembly 110 and the electrolyte are contained in the housing 120. As an example, the electrolyte may be liquid, gel or solid.

[0084] As an example, the housing 120 may be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell 121), or an aluminum-plastic film. In some embodiments, the housing 120 may be a sealed structure or a non-sealed structure. As an example, when the housing 120 is a non-sealed structure, the housing 120 plays a role in protecting the electrode assembly 110, and a sealed bag is also included between the housing 120 and the electrode assembly 110, and the sealed bag is used to encapsulate the electrode assembly 110 and the electrolyte. Specifically, the sealed bag may be a bag-shaped insulating member or an aluminum-plastic film. When the housing 120 is a sealed structure, it is used to encapsulate components such as the electrode assembly 110 and the electrolyte.

[0085] Please continue reading Figure 4 and Figure 5The electrode assembly 110 includes a main body 113 and a plurality of pole tabs 111 extending from the main body 113. The plurality of pole tabs 111 include a positive pole tab 111A and a negative pole tab 111B. The main body 113 includes a plurality of pole sheet layers 1131 and a plurality of diaphragm layers 1132 stacked in layers. The pole sheet layers 1131 and the diaphragm layers 1132 are alternately stacked. The polarities of any two adjacent pole sheet layers 1131 in the plurality of pole sheet layers 1131 are opposite, that is, the polarity of one of the two adjacent pole sheet layers 1131 is positive and the polarity of the other is negative. The diaphragm layer 1132 can separate the two adjacent pole sheet layers 1131.

[0086] Each diaphragm layer 1132 extends beyond the edge of the pole piece layer 1131 in the height direction of the main body 113. Along the height direction of the main body 113, the housing 120 is formed with one receiving space 123 located on one side of the main body 113 or two receiving spaces 123 located on different sides of the main body 113. In other words, at least one receiving space 123 is formed in the housing 120. Figures 4 to 7 A pole ear 111 extends from the end face of the main body 113 toward the receiving space 123, and each diaphragm layer 1132 extends from a lug 1133 toward the end of the receiving space 123. The lug 1133 is integrally connected to the corresponding diaphragm layer 1132, and the lug 1133 and the pole ear 111 on the same side of the main body 113 are accommodated in the same receiving space 123; and the lug 1133 is fixedly connected to the outer shell 120.

[0087] The height direction of the main body 113 is shown as the Z axis in the various figures of the present application. It can be understood that the height direction of the main body 113 can be parallel to the height direction of the shell 120. In this example, a receiving space 123 is formed at the top and / or bottom of the shell 120. The main body 113 has two end faces along its own height direction. For ease of understanding, the two end faces are respectively referred to as the first end face and the second end face. Along the height direction of the main body 113, the pole piece layer 1131 has opposite edges, and the diaphragm layer 1132 has two ends. For ease of understanding, the two end portions are respectively referred to as the first end face and the second end face. Among them, the first end face and the first end face are facing the top of the shell 120, and the second end face and the second end face are facing the bottom of the shell 120.

[0088] As an example, two receiving spaces 123 are formed in the housing 120, and along the height direction of the main body 113, the two receiving spaces 123 are respectively located on both sides of the main body 113. In this example, the positive electrode tab 111A and the negative electrode tab 111B extend from the two end surfaces of the main body 113 respectively. For example, the positive electrode tab 111A extends from the first end surface, the negative electrode tab 111B extends from the second end surface, and the two ends of each diaphragm layer 1132 extend with lugs 1133. The positive electrode tab 111A and all the lugs 1133 extending from the first end are accommodated in one receiving space 123, and the negative electrode tab 111B and all the lugs 1133 extending from the second end are accommodated in another receiving space 123. For another example, the positive electrode tab 111A extends from the second end surface, and the negative electrode tab 111B extends from the first end surface. During operation of such battery cell 11, when the internal temperature reaches the shrinkage temperature due to thermal runaway, overcharging, etc., the total volume of the diaphragm layer 1132 tends to decrease, and the two ends of the diaphragm layer 1132 tend to migrate toward the middle. Since lugs 1133 extend from both ends of each diaphragm layer 1132, and the lugs 1133 are fixedly connected to the housing 120, the connection between the lugs 1133 and the housing 120 exerts a certain pulling effect on the diaphragm layer 1132, so that the shrinkage of the two ends of each diaphragm layer 1132 is limited, thereby reducing the possibility of the edge of the pole piece layer 1131 being exposed due to the reduction in the height of the diaphragm layer 1132, thereby reducing the risk of short circuit caused by the edge contact of the pole piece layers 1131 with opposite polarities.

[0089] As an example, a receiving space 123 is formed in the housing 120. Taking the receiving space 123 located on one side of the main body 113 as an example, in this example, a lug 1133 extends from the first end of each diaphragm layer 1132, and the positive electrode lug 111A and the negative electrode lug 111B both extend from the first end surface, then the positive electrode lug 111A, the negative electrode lug 111B and all the lugs 1133 are protruding from one side of the main body 113 and accommodated in the receiving space 123. During the operation of such a battery cell 11, when the internal temperature reaches the contraction temperature due to thermal runaway, overcharging, etc., the total volume of the diaphragm layer 1132 tends to decrease, and the two ends of the diaphragm layer 1132 tend to migrate toward the middle. Since the first end of each diaphragm layer 1132 extends with a lug 1133, and the lug 1133 is fixedly connected to the housing 120, the connection between the lug 1133 and the housing 120 exerts a certain pulling effect on the diaphragm layer 1132, so that the contraction of the first end of each diaphragm layer 1132 is limited. In addition, the second end of each diaphragm layer 1132 also extends beyond the pole piece layer 1131, and a certain amount of contraction is reserved for the second end of the diaphragm 1138, so that at least to a certain extent, the possibility of the second end of the diaphragm layer 1132 contracting and causing the edge of the pole piece layer 1131 to be exposed toward the second end and contact short circuit can be reduced.

[0090] In summary of the foregoing description, the battery cell 11 of this embodiment is designed to have a receiving space 123 located on one side of the main body 113 or two receiving spaces 123 located on different sides of the main body 113 in the shell 120, and each diaphragm layer 1132 has a lug 1133 extending toward the end of the receiving space 123, and the lug 1133 is fixedly connected to the shell 120. During the operation of the battery cell 11, when the internal temperature reaches the shrinkage temperature due to thermal runaway, overcharging, etc., the end of each diaphragm layer 1132 protruding with the lug 1133 is limited in shrinkage by virtue of the connection between the lug 1133 and the shell 120, so that the probability of each diaphragm layer 1132 being isolated and failing due to thermal shrinkage can be effectively reduced, thereby reducing the possibility of short-circuiting and generating heat due to the contact of the edges of any two adjacent electrode layers 1131, thereby improving the thermal stability of the battery cell 11, thereby reducing the safety hazards of the battery cell 11.

[0091] In addition, since the lug 1133 is integrally connected to the diaphragm layer 1132, the lug 1133 also has an insulating isolation capability, and the lug 1133 is not limited to being connected to a component made of an insulating material on the housing 120, but can also be connected to a component made of a metal material on the housing 120 without causing a short circuit. Second, the lug 1133 and the diaphragm layer 1132 are an integral part and do not need to be assembled.

[0092] It is understood that the electrode assembly 110 may be a winding structure or a laminated structure, and this embodiment does not impose any specific limitation on this. Figure 4 and Figure 5 As shown, the main body 113 may be a winding structure formed by stacking two diaphragms 1138 and two pole pieces 1135 with opposite polarities and winding them along a winding direction. After each pole piece 1135 is wound, a plurality of pole piece layers 1131 arranged in sequence along the winding direction are formed, and after each diaphragm 1138 is wound, a plurality of diaphragm layers 1132 arranged in sequence along the winding direction are formed. It can be understood that Figure 7 As shown, each diaphragm 1138 of the wound main body 113 extends a plurality of lugs 1133 along its width direction, and the plurality of lugs 1133 are arranged at intervals along the length direction of the diaphragm 1138 , so that each diaphragm layer 1132 is connected with a lug 1133 .

[0093] Among them, the pole piece 1135 includes a current collector and an active material arranged on at least one surface of the current collector. The current collector has two surfaces opposite to each other in its own thickness direction, and the active material is arranged on any one or both of the two opposite surfaces of the current collector. The current collector not coated with the active material protrudes from the current collector coated with the active material, and the current collector not coated with the active material serves as the pole ear 111. Among them, the two pole pieces 1135 with opposite polarities are respectively the positive pole piece and the negative pole piece, and the battery cell 11 mainly relies on the movement of metal ions between the positive pole piece and the negative pole piece to work. Taking lithium-ion batteries as an example, the material of the current collector of the positive pole piece can be aluminum, and the active material material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc.; the material of the current collector of the negative pole piece can be copper, and the active material material can be carbon or silicon, etc.

[0094] As an example, please refer to Figure 4 and Figure 5 , the winding structure can be flat, the battery cell 11 includes two electrode assemblies 110, the flat main body parts 113 of the two electrode assemblies 110 are stacked along the thickness direction of the main body part 113, and the shell 120 is in the shape of a rectangular parallelepiped. Of course, the number of electrode assemblies 110 is not limited to two, and can also be three or more. In this way, the number of electrode assemblies 110 is large, which is conducive to improving the energy density of the battery cell 11. The flat main body 113 includes a straight section 1136 formed by winding and a curved section 1137 connected to the straight section 1136. The lug 1133 can extend from the straight section 1136, such as Figure 4 and Figure 5 As shown, lug 1133 may also extend from curved section 1137 .

[0095] As an example, the winding structure can be replaced with a cylindrical shape, and the housing 120 is also cylindrical. In this example, the battery cell 11 is cylindrical.

[0096] In some embodiments of the present application, the main body 113 can be replaced by a laminated structure instead of a winding structure. Specifically, the main body 113 is a laminated structure formed by stacking a plurality of pole sheets 1131 and a plurality of diaphragm layers 1132. The polarity of some of the plurality of pole sheets 1131 is positive, and the polarity of the remaining portions is negative. As an example, the battery cell 11 may also include a plurality of electrode assemblies 110, and the plurality of electrode assemblies 110 are stacked along the stacking direction of the main body 113. In this way, the number of electrode assemblies 110 is large, which is conducive to improving the energy density of the battery cell 11.

[0097] In the battery cell 11 disclosed herein, the material of the separator 1138 may be polypropylene (PP) or polyethylene (PE), etc., and this embodiment does not impose any specific limitation on this.

[0098] It is understandable that all lugs 1133 may be connected to the housing 120 individually, or a plurality of lugs 1133 may be stacked and connected to form a lug portion 1134 , and the lug portion 1134 may be connected to the housing 120 .

[0099] In some embodiments of the present application, all the lugs 1133 accommodated in the same accommodating space 123 can be arranged as one lug portion 1134 or multiple lug portions 1134 spaced apart from each other; each lug portion 1134 is formed by a plurality of lugs 1133 stacked and connected, and the lug portion 1134 is fixedly connected to the housing 120.

[0100] As an example, see Figure 4 and Fig. 9 As shown, a lug 1133 extends from the first end of each diaphragm layer 1132 , and the lugs 1133 of each diaphragm layer 1132 are sequentially arranged in a stacked arrangement along the thickness direction of the diaphragm layer 1132 , and then the lugs 1133 are connected to form a lug portion 1134 .

[0101] As an example, see Fig. 9 As shown, a lug 1133 extends from the first end of each diaphragm layer 1132, and the lugs 1133 of some diaphragm layers 1132 and the lugs 1133 of another diaphragm layer 1132 can be designed to be non-opposite along the thickness direction of the diaphragm layer 1132, so that the lugs 1133 of some diaphragm layers 1132 are stacked and connected to form one lug portion 1134, and the lugs 1133 of another diaphragm layer 1132 are stacked and connected to form another lug portion 1134. In this example, all the lugs 1133 accommodated in the same receiving space 123 are arranged into two lug portions 1134, and the lugs 1133 included in the two lug portions 1134 belong to different diaphragm layers 1132.

[0102] As an example, see Fig. 9 As shown, the first end of each diaphragm layer 1132 can extend K mutually spaced lugs 1133, K is a positive integer greater than or equal to 2, and each lug 1133 of any diaphragm layer 1132 is stacked and connected with a lug 1133 of the remaining diaphragm layers 1132, so that K lug portions 1134 can be formed, and the lugs 1133 included in each lug portion 1134 belong to each diaphragm layer 1132 respectively.

[0103] See also Fig. 9 As shown, a lug 1133 may be extended from the end of any one of the plurality of diaphragm layers 1132 , or a plurality of lugs 1133 spaced apart from each other may be extended.

[0104] By arranging all the lugs 1133 accommodated in the same accommodating space 123 into one lug portion 1134 or multiple lug portions 1134, on the one hand, the multiple lugs 1133 constituting the lug portion 1134 are stacked and arranged, which can reduce the space occupied by the lugs 1133 in their own width direction compared to the multiple lugs 1133 being spaced apart from each other. On the other hand, compared to each lug 1133 being individually connected to the outer shell 120, this can reduce the assembly and connection steps, which is beneficial to improving the preparation efficiency of the battery cell 11.

[0105] In the embodiment where all the lugs 1133 accommodated in the same receiving space 123 are arranged as a plurality of lug portions 1134, the number of lugs 1133 included in the lug portion 1134 may be equal to the number of diaphragm layers 1132, that is, the plurality of lugs 1133 constituting the lug portion 1134 belong to each diaphragm layer 1132. Alternatively, the number of lugs 1133 included in the lug portion 1134 is less than the number of diaphragm layers 1132.

[0106] In the embodiment where all lugs 1133 accommodated in the same receiving space 123 are arranged as a plurality of lug portions 1134, the main body portion 113 is a flat winding structure, such as Figure 5 As shown, a plurality of lugs 1134 are arranged at intervals along the circumference of the main body 113. The lugs 1134 can be arranged at the straight section 1136 of the main body 113 or at the curved section 1137 of the main body 113. If the main body 113 is a cylindrical winding structure, the plurality of lugs 1134 are arranged at intervals along the circumference of the main body 113. If the main body 113 is a laminated structure, the plurality of lugs 1134 are arranged at intervals along the width direction of the main body 113.

[0107] In some embodiments of the present application, Figure 4 and Figure 5 As shown, a receiving space 123 is formed in the housing 120, and the positive electrode tab 111A and the negative electrode tab 111B extend from the same end of the main body 113, and the positive electrode tab 111A and the negative electrode tab 111B are protrudingly arranged on the same side of the main body 113, and the positive electrode tab 111A and the negative electrode tab 111B are arranged at intervals along a preset direction, and the preset direction is perpendicular to the height direction of the main body 113 and the thickness direction of the main body 113. In this example, at least part of the protruding ear portion 1134 can be arranged between the positive electrode tab 111A and the negative electrode tab 111B.

[0108] As an example, when there is one lug portion 1134, the lug portion 1134 is disposed between the positive electrode lug 111A and the negative electrode lug 111B. As an example, when there are multiple lug portions 1134, one lug portion 1134, multiple lug portions 1134, or all lug portions 1134 are disposed between the positive electrode lug 111A and the negative electrode lug 111B.

[0109] For the flat winding main body 113 , the preset direction refers to the width direction of the main body 113 . For the laminated main body 113 , the preset direction is also the width direction of the main body 113 .

[0110] In the present embodiment, at least part of the lugs 1134 are designed to be located between the positive electrode lug 111A and the negative electrode lug 111B. The lugs 1134 between the positive electrode lug 111A and the negative electrode lug 111B can play an isolating role, so that the positive electrode lug 111A and the negative electrode lug 111B are isolated and do not contact each other to avoid a short circuit.

[0111] In some embodiments of the present application, Figure 4 and Figure 5 As shown, the lug portions 1134 may be symmetrically arranged about the longitudinal center line of the main body portion 113 .

[0112] For the cylindrical winding body 113, the longitudinal centerline is the axis of the body 113. When there are multiple lugs 1134, the multiple lugs 1134 are spaced and evenly distributed around the longitudinal centerline.

[0113] For the winding main body 113, the longitudinal center line of the main body 113 is perpendicular to the width direction and thickness direction of the main body 113. In the various drawings of the present application, the X-axis and the Y-axis represent the width direction and thickness direction of the main body 113, respectively. When there is one lug 1134, the lug 1134 is protruding from one side of the main body 113 and corresponds to the middle of the main body 113 in its own width direction. When there are multiple lugs 1134, the multiple lugs 1134 are spaced and evenly distributed along the width direction of the main body 113, and one of the lugs 1134 corresponds to the middle of the main body 113 in its own width direction.

[0114] As an example, when there are multiple lug portions 1134 , both the positive electrode lug 111A and the negative electrode lug 111B may be located between two adjacent lug portions 1134 .

[0115] The lugs 1134 are designed to be symmetrically arranged about the longitudinal center line of the main body 113. When there is only one lug 1134, for the wound main body 113, the lug 1134 can be arranged to correspond to the middle of the main body 113 in its own width direction, so that the pulling effect of the connection between the lug 1134 and the shell 120 on each diaphragm layer 1132 is also located in the middle of the diaphragm layer 1132, so that the diaphragm layer 1132 is evenly stressed. When there are multiple lugs 1134, the pulling effect of the connection between each lug 1134 and the shell 120 on each diaphragm layer 1132 is symmetrically distributed with respect to the longitudinal center line of the main body 113, so that the diaphragm layer 1132 is evenly stressed. In this way, the possibility of the diaphragm layer 1132 being broken due to uneven stress can be reduced.

[0116] In some embodiments of the present application, the connection method of the multiple lugs 1133 constituting the lug portion 1134 may be implemented as an adhesive connection, or may be implemented as a hot melt connection, that is, the multiple lugs 1133 are subjected to a hot melt treatment.

[0117] The multiple lugs 1133 can be reliably connected by adhesive connection or hot melt connection, so that the structure of the lug portion 1134 formed by the multiple lugs 1133 is reliable, so that the multiple lugs 1133 forming the lug portion 1134 are less likely to become loose during the transportation of the battery cell 11.

[0118] In some embodiments of the present application, Figures 3 to 5 As shown, the housing 120 may include a housing 121 and an end cap assembly 122, the housing 121 having an opening, the end cap assembly 122 including an end cap 1221 and a lower plastic part 1222, the end cap 1221 covers the opening, and the lower plastic part 1222 is disposed on a side of the end cap 1221 facing the electrode assembly 110. The housing 121 may have one opening, and the end cap assembly 122 may be one corresponding one, or the housing 121 may have multiple openings, and the end cap assembly 122 may be multiple corresponding ones.

[0119] As an example, Figure 4 , Figure 5 and Fig.11As shown, the shell 121 may be provided with an opening, and the end cap assembly 122 is one and is disposed at the top of the shell 121. A receiving space 123 is correspondingly formed in the shell 121, and the receiving space 123 is located between the main body 113 and the end cap assembly 122, that is, on the upper side of the main body 113. The positive pole tab 111A and the negative pole tab 111B both extend from the first end surface of the main body 113, and a lug 1133 extends from the first end of each diaphragm layer 1132. The positive pole tab 111A, the negative pole tab 111B and the lug 1133 are all protruding from the upper side of the main body 113. In this example, there are various ways to achieve the fixed connection of the lug 1133 to the shell 120. The lug 1133 can be fixedly connected to the lower plastic part 1222, or fixedly connected to the lower surface of the end cap 1221, or connected to the inner wall surface of the shell 121, and the connection is located at the top of the shell 121 and close to the opening. In the manner in which the lug 1133 is fixedly connected to the lower plastic part 1222, when preparing the battery cell 11, the prepared electrode assembly 110 can be first connected to the lower plastic part 1222, and then the connected electrode assembly 110 and end cover assembly 122 can be moved and assembled, so that the electrode assembly 110 is moved into the shell 121 through the opening until the end cover 1221 covers the opening, and then the end cover 1221 is connected to the shell 121 by welding or the like.

[0120] As an example, the shell 121 may be provided with an opening, and the end cap assembly 122 is one and is disposed at the bottom of the shell 121. A receiving space 123 is correspondingly formed in the shell 121, and the receiving space 123 is located between the main body 113 and the end cap assembly 122, that is, the lower part of the main body 113. The positive pole tab 111A and the negative pole tab 111B both extend from the second end surface of the main body 113, and a lug 1133 extends from the second end of each diaphragm layer 1132. The positive pole tab 111A, the negative pole tab 111B and the lug 1133 are all protruding from the lower side of the main body 113. In this example, there are various ways to achieve the fixed connection of the lug 1133 to the shell 120. The lug 1133 can be fixedly connected to the lower plastic part 1222, or fixedly connected to the upper surface of the end cap 1221, or connected to the inner wall surface of the shell 121, and the connection is located at the bottom end of the shell 121 and close to the opening.

[0121] As an example, the shell 121 may be provided with openings at both the top and bottom ends, and there are two end cover assemblies 122, and the end covers 1221 of the two end cover assemblies 122 are respectively provided to cover the top opening and the bottom opening. Two receiving spaces 123 are correspondingly formed in the shell 121, and the two receiving spaces 123 are respectively located on both sides of the main body 113. The positive pole tab 111A and the negative pole tab 111B extend from the two end surfaces of the main body 113, and lugs 1133 extend from both ends of each diaphragm layer 1132. Taking the main body 113 as a cylindrical winding structure as an example, the battery cell 11 in this example can be a cylindrical battery cell 11 with a positive terminal and a negative terminal respectively provided at both ends.

[0122] In the method of connecting the lug 1133 to the lower plastic part 1222, since the materials of the diaphragm 1138 and the lower plastic part 1222 are both polymers, the material properties are similar, so the restrictions on the connection method between the two due to the large difference in material properties can be reduced, which is convenient for installation and can help improve the preparation efficiency of the battery cell 11. For the sake of simplicity, the following description takes the connection between the lug 1133 and the lower plastic part 1222 as an example.

[0123] In some embodiments of this application, please combine Figure 4 , Figure 5 , Figures 11 to 13 The lower plastic part 1222 can be configured to include a plastic body 1223 and a protrusion 1224 , the protrusion 1224 is arranged on a side of the plastic body 1223 facing away from the end cover 1221 , and the lug 1133 is connected to the protrusion 1224 .

[0124] Taking the case where the shell 120 is in the shape of a cuboid, that is, the battery cell 11 is a square shell battery cell 11, as an example, the end cap 1221 is correspondingly in the shape of a rectangle. Among them, the protrusion 1224 may include, for example, two bosses and two ribs, the two bosses are arranged at intervals along the length direction of the end cap 1221 and are respectively located on both sides of the end cap 1221, the two bosses may abut against the electrode assembly 110 to limit the movement of the electrode assembly 110 in the vertical direction, and reduce the risk of the tab 111 and the tab 1133 being pulled up and down and torn, and the two ribs extend along the length direction of the end cap 1221 and are arranged at intervals along the width direction of the end cap 1221. By arranging the ribs in the length direction of the lower plastic body 1223, the possibility of bending and deformation caused by excessive length of the lower plastic can be reduced.

[0125] Depending on the position of the lug 1133 relative to the main body 113, the lug 1133 may be connected to the boss or to the rib. Figure 4 , Figure 5 , Figures 11 to 13As shown, when the main body 113 is a flat winding structure, the width direction of the main body 113 is parallel to the length direction of the end cap 1221, and the thickness direction of the main body 113 is parallel to the width direction of the end cap 1221. The lug 1133 protruding from the straight section 1136 can be connected to the rib. In an embodiment not shown in the figure, the lug 1133 protruding from the curved section 1137 can be connected to the boss.

[0126] The lower plastic part 1222 is designed to include a plastic body 1223 and a protruding portion 1224 , which is beneficial to improving the structural strength of the lower plastic part 1222 .

[0127] In some embodiments, the plastic body 1223 and the protrusion 1224 can be integrally formed, which, on the one hand, helps to save the assembly process of the plastic body 1223 and the protrusion 1224, and on the other hand, helps to further improve the structural strength of the lower plastic part 1222 without increasing the cost.

[0128] In some embodiments of this application, please refer to Fig.12 The protrusion 1224 and the plastic body 1223 can be assembled and connected, and the protrusion 1224 and the plastic body 1223 together define a groove, and a portion of the lug 1133 is disposed in the groove.

[0129] By arranging the protrusion 1224 and assembling it with the plastic body 1223 , the protrusion 1224 can be processed and constructed into a complex shape, so that the protrusion 1224 and the plastic body 1223 can define a groove for accommodating the lug 1133 .

[0130] There are various ways to implement the partial arrangement of the lug 1133 in the groove. For example, the lug 1133 is partially arranged in the groove by hot pressing. Alternatively, the lug 1133 is partially arranged in the groove by adhesive. Alternatively, the lug 1133 is partially clamped in the groove by snap-fitting. In this way, the lug 1133 can be arranged in the groove more stably and reliably, thereby improving the connection reliability between the lug 1133 and the lower plastic part 1222.

[0131] In some embodiments of the present application, the lug 1133 and the lower plastic part 1222 may be connected by bonding, or the lug 1133 and the lower plastic part 1222 may be connected by hot melting.

[0132] The lug 1133 and the lower plastic are connected by an adhesive connection method or a hot melt connection method, and the connection method is simple and reliable.

[0133] As an example, when the lower plastic part 1222 includes the plastic body 1223 and the protrusion 1224 , the lugs 1133 can be bonded or hot-melt connected to the side of the protrusion 1224 facing the outside of the housing 120 .

[0134] In some embodiments of the present application, Figure 4 , Figure 5 , Figures 11 to 13 As shown, the lug portion 1134 can be configured to include a connected straight portion 1134a and a connecting portion 1134b, the straight portion 1134a is in contact with the end surface of the main body 113, the connecting portion 1134b is folded relative to the straight portion 1134a in a direction away from the main body 113, and one end of the connecting portion 1134b away from the straight portion 1134a is fixedly connected to the housing 120. The tab 111 can be folded into a plurality of overlapping segments spaced apart along the height direction of the main body 113, and any two adjacent overlapping segments are opposite and connected.

[0135] That is, the straight portion 1134a and the connecting portion 1134b are connected by a bend. According to the actual connection requirements and working conditions between the connecting portion 1134b and the housing 120, the connecting portion 1134b can be straight or bent. Fig.12 As shown, the connecting portion 1134b may be bent once. Fig.13 As shown, the connecting portion 1134b can be bent twice.

[0136] In combination with the foregoing description, one end of the connection portion 1134b of the lug portion 1134 can be bonded or hot-melt connected to the side of the protrusion 1224 facing the outside of the housing 120, or can extend into the above-mentioned groove to be accommodated and fixed in the groove.

[0137] In this embodiment, the lug portion 1134 and the pole ear 111 are bent and folded to be accommodated in a receiving space 123, so that the space occupied by the lug portion 1134 and the pole ear 111 in the height direction of the battery cell 11 can be reduced, thereby effectively improving the overall energy density of the battery cell 11. When the capacity of the battery cell 11 is constant, the volume of the battery cell 11 can be reduced, making the battery easier to install in an electrical device with limited height space; or when the volume of the battery cell 11 is constant, the capacity can be increased and the battery life can be extended.

[0138] Optionally, the heights of the plurality of lugs 1133 constituting the lug portion 1134 may be the same. Figure 7 As shown, during preparation, the diaphragm 1138 is cut to form a plurality of lugs 1133 , and the heights of the plurality of lugs 1133 are the same.

[0139] Optionally, the heights of the plurality of lugs 1133 constituting the lug portion 1134 may also be different. In some embodiments of the present application, the lug portion 1134 has a first surface and a second surface, the first surface is connected to the housing 120, and the second surface is away from the first surface. The height of each lug 1133 constituting the lug portion 1134 may gradually increase from the first surface to the second surface in a flattened state.

[0140] like Fig.13 As shown, the lug 1134 is bonded or hot-melted to the side of the protrusion 1224 facing the outside of the shell 121, and the first surface of the lug 1134 refers to the side of the lug 1134 facing the protrusion 1224, and the second surface refers to the side of the lug 1134 facing away from the protrusion 1224. That is, along the stacking direction of the lug 1134, the closer the lug 1133 is to the protrusion 1224, the smaller the height is, and the farther the lug 1133 is from the protrusion 1224, the greater the height is. Specifically, taking the main body 113 as a winding structure as an example, as shown in FIG. Figure 8 As shown, during preparation, the diaphragm 1138 is cut to form a plurality of lugs 1133, and the heights of the plurality of lugs 1133 are different. The lugs 1133 are wound in sequence along the winding direction, so that the heights of the lugs 1133 of the stacked lug portion 1134 gradually change. It can also be understood that along the thickness direction of the lug portion 1134 and from the first surface to the second surface, the distance from the lugs 1133 included in the lug portion 1134 to the side of the protruding portion 1224 gradually increases. Based on this, in this embodiment, the lug portion 1134 is designed so that the height of the lugs 1133 included therein can gradually increase from the first surface to the second surface in the flattened state, so that the height of the lugs 1133 in the lug portion 1134 far from the first surface is greater, thereby reducing the possibility of the lugs 1133 far from the first surface and the diaphragm layer 1132 integrally connected thereto being broken by tension.

[0141] In some embodiments of the present application, the height of the receiving space 123 is h, and the sum of the height of the lug 1133 in a flattened state and the height of the portion of the diaphragm layer 1132 that extends beyond the pole piece layer 1131 may be greater than h.

[0142] As an example, the heights of the multiple lugs 1133 constituting the lug portion 1134 in the flattened state are all the same and are H1, the height of the portion of the diaphragm layer 1132 that exceeds the pole piece layer 1131 is H2, H1+H2=H, H>h. In other words, the sum of the heights of the multiple lugs 1133 constituting the lug portion 1134 in the flattened state and the height of the portion of the diaphragm layer 1132 that exceeds the pole piece layer 1131 is H.

[0143] As an example, the heights of the multiple lugs 1133 constituting the lug portion 1134 in the flattened state are different, and the heights of the multiple lugs 1133 constituting the lug portion 1134 in the flattened state are not equal to the sum of the height H2 of the portion of the diaphragm layer 1132 extending beyond the pole piece layer 1131, and are all greater than h.

[0144] With this design, the lug portion 1134 and the pole lug 111 are folded and accommodated in the accommodating space 123, so as to reduce the space occupied by the lug portion 1134 and the pole lug 111 in the height direction of the battery cell 11, and also increase the height of the lug 1133 in the flattened state as much as possible to facilitate operation during the preparation process of the battery cell 11.

[0145] In some embodiments of the present application, the difference between the sum of the height of the lug 1133 in the flattened state and the height of the portion of the diaphragm layer 1132 extending beyond the pole piece layer 1131 and h can be designed to be greater than or equal to 2 mm and less than or equal to 15 mm.

[0146] As an example, Figure 7 As shown, the height of the lugs 1133 in the flattened state is the same and is H1, then the sum of the height of the lugs 1133 in the flattened state and the height of the portion of the diaphragm layer 1132 that exceeds the pole piece layer 1131 is H, then 2mm≤Hh≤15mm. Among them, the value of Hh can be any one of 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm and 15 mm.

[0147] Thus, the height of the lug 1133 in the flattened state is moderate: on the one hand, it is not too small to ensure reliable connection with the housing 120 when folded, and on the other hand, it is not too large to reduce the material consumption of the diaphragm layer 1132, so as to save manufacturing costs.

[0148] In some embodiments of the present application, along the height direction of the main body 113, the tab 111 may exceed each lug 1133 located in the same receiving space 123. In other words, the height of the tab 111 in the straight state is greater than the height of the lug 1133 in the flattened state.

[0149] With this design, the lug 1134 and the lug 111 are folded and accommodated in the accommodating space 123 to reduce the space occupied by the lug 1134 and the lug 111 in the height direction of the battery cell 11. In addition, the lug 111 extends beyond the lug 1133, so that the positive pole lug 111A can extend to connect with the positive terminal 130 of the battery cell 11, and the negative pole lug 111B can extend to connect with the negative terminal 140 of the battery cell 11.

[0150] In some embodiments of the present application, along the height direction of the main body 113 , the distance that the pole lug 111 exceeds each lug 1133 is greater than or equal to 2 mm and less than or equal to 20 mm.

[0151] As an example, Figure 7 As shown, the height of each lug 1133 in the flattened state is the same and is H1, then the difference between the height of the pole ear 111 in the straightened state and the height of each lug 1133 in the flattened state is the same and is N, then 2mm≤N≤20mm. Among them, the value of N can be specifically selected from any one of 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm and 20 mm.

[0152] As an example, Figure 8 As shown, the heights of the lugs 1133 in the flattened state are different, and the differences between the height of the tab 111 in the straightened state and the heights of the lugs 1133 in the flattened state are different, but the difference ranges from [2 mm, 20 mm].

[0153] It has been verified that by designing the distance of the pole ear 111 beyond each lug 1133 to be greater than or equal to 2 mm and less than or equal to 20 mm, the pole ear 111 can extend beyond the lug 1133 and the risk of short circuit caused by contact between the pole ear 111 and components such as the metal shell 121 can be reduced.

[0154] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below.

[0155] Embodiment 1

[0156] In the implementation manner of the present application, as 4, Figure 5 , Figures 11 to 13As shown, the present application proposes a square shell battery cell 11, comprising: a shell 121, an end cap assembly 122 and two electrode assemblies 110 contained in the shell 121. The top of the shell 121 is provided with an opening, and the end cap assembly 122 is provided with one, and the end cap assembly 122 includes an end cap 1221 and a lower plastic part 1222, the end cap 1221 covers the opening, and the lower plastic part 1222 is provided on the side of the end cap 1221 facing the electrode assembly 110, and a receiving space 123 is formed between the two electrode assemblies 110 and the end cap assembly 122, and the height of the receiving space 123 is h. The shell 121 is in the shape of a rectangular parallelepiped, and the two electrode assemblies 110 are stacked along the width direction of the shell 121.

[0157] The lower plastic part 1222 is configured to include a plastic body 1223 and a protrusion 1224, and the protrusion 1224 is arranged on the side of the plastic body 1223 facing away from the end cover 1221. The protrusion 1224 includes, for example, two bosses and two ribs, the two bosses are arranged at intervals along the length direction of the end cover 1221 and are respectively located on both sides of the end cover 1221, the two bosses can abut against the electrode assembly 110, and the two ribs extend along the length direction of the end cover 1221 and are arranged at intervals along the width direction of the end cover 1221.

[0158] The structures of the two electrode assemblies 110 are similar. The structure of any electrode assembly 110 is that the electrode assembly 110 includes a main body 113 and two tabs 111 extending from the main body 113 , and the two tabs 111 are respectively a positive tab 111A and a negative tab 111B. The main body 113 is a flat winding structure formed by two stacked diaphragms 1138 and two pole pieces 1135 with opposite polarities stacked and wound along a winding direction. After each pole piece 1135 is wound, a plurality of pole piece layers 1131 arranged in sequence along the winding direction are formed. After each diaphragm 1138 is wound, a plurality of diaphragm layers 1132 arranged in sequence along the winding direction are formed. The main body 113 includes a plurality of pole piece layers 1131 and a plurality of diaphragm layers 1132. The pole piece layers 1131 and the diaphragm layers 1132 are alternately stacked. The polarities of any two adjacent pole piece layers 1131 are opposite, that is, the polarity of one of the two adjacent pole piece layers 1131 is positive and the polarity of the other is negative. The diaphragm layer 1132 can separate the two adjacent pole piece layers 1131.

[0159] Along the height direction of the shell 121, the main body 113 has a first end surface facing the end cap assembly 122, each diaphragm layer 1132 has a first end portion facing the end cap assembly 122, the positive pole ear 111A and the negative pole ear 111B extend from the first end surface, and one or more lugs 1133 extend from the first end portion of each diaphragm layer 1132. All lugs 1133 are arranged into three lug portions 1134, and each lug portion 1134 is formed by stacking and connecting a plurality of lugs 1133. Along the length direction of the shell 121, the lug portions 1134 and the lugs 111 are alternately spaced, and the positive pole ear 111A and the negative pole ear 111B are both located between two adjacent lug portions 1134. In addition, the three lug portions 1134 are all protruding from the straight section 1136 of the main body 113, and one of the three lug portions 1134 located in the middle is symmetrically arranged about the longitudinal center line of the main body 113.

[0160] The tab 111 is folded into two overlapping sections spaced apart along the height direction of the main body 113, and the two overlapping sections are opposite and connected, that is, the tab 111 is folded into a U-shape. The lug portion 1134 is bent to form a straight portion 1134a and a connecting portion 1134b connected to each other, the straight portion 1134a is in contact with the first end surface of the main body 113, and the connecting portion 1134b is folded in a direction away from the main body 113 relative to the straight portion 1134a.

[0161] The ends of the connecting portions 1134b of the three lug portions 1134 away from the straight portion 1134a are all bonded or hot-melt connected to the ribs of the lower plastic part 1222 on the side facing the outside of the shell 121. Along the stacking direction of the lug portions 1134, from close to the ribs to away from the ribs, the heights of the multiple lugs 1133 included in the three lug portions 1134 in the flattened state gradually increase. The sum of the height of each lug 1133 in the flattened state and the height H2 of the portion of the diaphragm layer 1132 that exceeds the pole piece layer 1131 is greater than h. Moreover, the difference between the sum of the height of each lug 1133 in the flattened state and the height H2 of the portion of the diaphragm layer 1132 that exceeds the pole piece layer 1131 minus h is greater than or equal to 2 mm and less than or equal to 15 mm.

[0162] Each pole lug 111 in the straightened state exceeds each lug 1133 , and the exceeding distance is greater than or equal to 2 mm and less than or equal to 15 mm.

[0163] Embodiment 2

[0164] This embodiment is similar to the first embodiment, except that the main body 113 of the electrode assembly 110 in the first embodiment is a winding structure. In this embodiment, the main body 113 of the electrode assembly 110 is a laminated structure formed by stacking a plurality of electrode layers 1131 and a plurality of diaphragm layers 1132 .

[0165] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: The housing comprises a shell and an end cover assembly, wherein the shell has an opening, the end cover assembly comprises an end cover and a lower plastic part, and the end cover covers the opening; An electrode assembly is contained in the housing, wherein the lower plastic part is disposed on a side of the end cap facing the electrode assembly; the electrode assembly comprises a main body and a plurality of pole ears extending from the main body, the main body comprises a plurality of pole sheet layers and a plurality of diaphragm layers stacked in layers, the pole sheet layers and the diaphragm layers are alternately stacked, any two adjacent pole sheet layers in the plurality of pole sheet layers have opposite polarities, and each diaphragm layer exceeds an edge of the pole sheet layer in a height direction of the main body; Wherein, along the height direction of the main body, a receiving space is formed in the shell, and the receiving space is located between the main body and the end cover assembly; the main body extends the pole ear from the end surface toward the receiving space, and each of the diaphragm layers extends a lug toward the end of the receiving space, the lug is integrally connected with the corresponding diaphragm layer, and the lug and the pole ear arranged on the same side of the main body are accommodated in the receiving space; all the lugs in the receiving space are arranged as one lug portion or a plurality of lug portions spaced from each other; each lug portion is formed by a plurality of lugs stacked and connected; The lug portion includes a connected straight portion and a connecting portion, the straight portion is in contact with the end surface of the main body, the connecting portion is folded away from the main body relative to the straight portion, and one end of the connecting portion away from the straight portion is fixedly connected to the lower plastic part.

2. The battery cell according to claim 1, characterized in that: The plurality of lugs constituting the lug portion are bonded or heat-fused.

3. The battery cell according to claim 1, characterized in that: A receiving space is formed in the shell, and the multiple tabs include a positive tab and a negative tab, the positive tab and the negative tab are protruded on the same side of the main body, the positive tab and the negative tab are spaced apart along a preset direction, and the preset direction is perpendicular to the height direction of the main body and the thickness direction of the main body; at least part of the protruding ear is arranged between the positive tab and the negative tab.

4. The battery cell according to claim 3, characterized in that: The lug portions are symmetrically arranged about a longitudinal center line of the main body portion.

5. The battery cell according to claim 1, characterized in that: The tab is folded into a plurality of overlapping segments spaced apart along a height direction of the main body, and any two adjacent overlapping segments are opposite and connected.

6. The battery cell according to claim 5, characterized in that: The height of the receiving space is h, and the sum of the height of the lug in a flattened state and the height of the portion of the diaphragm layer that extends beyond the pole piece layer is greater than h.

7. The battery cell according to claim 6, characterized in that: The difference between the sum of the height of the lug in the flattened state and the height of the portion of the diaphragm layer extending beyond the pole piece layer and h is greater than or equal to 2 mm and less than or equal to 15 mm.

8. The battery cell according to claim 5, characterized in that: Along the height direction of the main body, the pole ear exceeds each of the protruding ears located in the same receiving space.

9. The battery cell according to claim 8, characterized in that: Along the height direction of the main body, the distance that the pole ear exceeds each of the protruding ears is greater than or equal to 2 mm and less than or equal to 20 mm.

10. The battery cell according to claim 5, characterized in that: The lug portion has a first surface and a second surface, the first surface is connected to the housing, and the second surface is away from the first surface; the height of each lug constituting the lug portion gradually increases from the first surface to the second surface in a flattened state.

11. The battery cell according to claim 1, characterized in that: The lower plastic part comprises a plastic body and a protruding portion, wherein the protruding portion is arranged on a side of the plastic body facing away from the end cover, and the lug is connected to the protruding portion.

12. The battery cell according to claim 11, characterized in that: The protrusion is assembled and connected to the plastic body, and the protrusion and the plastic body together define a groove, and a portion of the lug is arranged in the groove.

13. The battery cell according to claim 11, characterized in that: The lug is connected to the lower plastic part by bonding, or the lug is connected to the lower plastic part by hot melting.

14. The battery cell according to any one of claims 1 to 10, characterized in that: The main body is a winding structure formed by stacking two diaphragms and two pole pieces with opposite polarities and winding them along a winding direction, each of the diaphragms has a plurality of diaphragm layers sequentially arranged along the winding direction, and each of the pole pieces has a plurality of pole piece layers sequentially arranged along the winding direction; Alternatively, the main body is a laminated structure formed by stacking the plurality of pole sheet layers and the plurality of diaphragm layers.

15. A battery device, characterized in that: include: A battery cell according to any one of claims 1 to 14.

16. An electrical device, characterized in that: include: The battery device according to claim 15, wherein the battery device is used to provide electrical energy.

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